Investigators said they didn't look for him sooner because there were no signs of foul play.

Jacob Hilkin

"I think everyone was hopeful that my son had just decided that he needed some time and wanted some space and that he'd come home," Marni Pierce said. "What they don't really know is my son. And my son would never walk away on his own, and any trouble he would've gotten in, no matter how big, he would've come to me."

Sunday's search brought no new answers for the family.

Pierce said she is grateful for the effort and continues to remain optimistic he'll come home.